1. Field of the Invention
The present invention relates to an autofocus apparatus and an image-pickup apparatus.
2. Description of the Related Art
Japanese Patent Laid-Open No. (“JP”) 2006-251065 hybrid autofocus (“AF”) that combines AF of a contrast method (“contrast AF” hereinafter”) with phase difference AF using a focus detector. JP 2009-003122 discloses an image-pickup element that includes focus detecting pixels and a pupil splitter and serves as phase difference AF (“SAF” (image-pickup plane phase difference AF) hereinafter)).
JP 2009-014850 discloses contrast AF that includes mountain-climbing AF used to search for a peak position of a contrast value by driving one of a focus lens and an image-pickup element in one direction, and wobbling AF configured to wobble the one to maintain focusing. For example, the mountain-climbing AF is performed for a large defocus amount and the wobbling AF is performed near an in-focus position to follow a moving body in the motion image photography using the contrast AF. JP 2007-323063 discloses a phase difference AF using a secondary imaging optical system.
The conventional contrast AF is disadvantageous because it takes much time to follow or cannot follow a moving object.